Unmounting /var partition I get 'device is busy'

I'm running my server from a usb key and I moved /var to another key in order to save some space and improve speed (helped a lot).

The problem I'm having though is that when shutting down / restarting I get:

umount2: Device or resource busy

Whilst trying to umount /var (formatted ext2)

I followed the tutorials on here to move /var although I did it this way:

Stopped all services / daemons (init 1) then copied the contents to the usb key, edited fstab, moved the original /var (then created the new 'blank' one with run and lock directories). Then rebooted... All works fine

If I do a 'shutdown now' and go back to the root console, sometimes I can see that rsyslogd and bizarrely mythtv-backend have restarted themselves (I can see that sometimes in the shutdown text output)... Why would they do that?

Upsettingly, even if I stop them and check /var is not being used (with lsof ) it still fails to umount?